Balanced pressure switch



BALANCED PRESSURE SWITCH Filed March 24, 1944 IN V EN TOR.

34 Fag/Wand A k/d/Mm Patented Dec. 10, 1946 UNITED STATES PATENT OFFICE BALANCED PRESSURE SWITCH Raymond L. Wiiliams, Arcadia, Calif.

Application March 24, 1944, Serial No. 527,875

2 Claims. 1

This invention relates to certain new and useful improvements in balanced pressure switches and has for its principal object the provision of an improved construction of the character hereinafter described, which will be highly efficient in use and economical in manufacture.

The present invention is designed for use pneumatic systems where it is desirabl for effective operation of the system that the pressure be completely stabilized throughout the system. The balanced pressure switch constituting the subject matter of my invention has been especially designed for use in connection with pneumatic welding machines and is to take the place of the pressure gauge usually employed in such machines, which gauges are manually set to maintain a stabilized pressure in the system.

Many attempts have been made to provide a means, for this purpose, which is automatic in its operation but prior to the advent of my balanced pressure switch these various means have proven unsatisfactory, unreliable, and costly in manufacture. It therefore was one of the principal objects of this invention to provide a pressure switch which would be automatic in its operation; one which would become effective for its intended purpose only upon a stabilized pressure in the pneumatic system whereby the pressure switch of my device, when operated by a balanced pressure, would be positive in its operation to set into circuit such of the mechanism as required for effective operation of the pneumatic system; and a balanced pressure switch which would be reliable and yet economical in manufacture.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of parts to be hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawin showing the preferred form of construction, and in which:

Fig. 1 is a sectional detail View of the balanced pressure switch embodied in my invention; and

Fig. 2 is a vertical sectional detail View taken substantially on line 22 of Fig. 1.

When the balanced pressure switch, hereinafter described, is used in a pneumatically operated resistance welding machine of a construction and type well-known in the art, it will serve to assure that the pressure on the electrodes is completely stabilized. This pressure switch comprises a housing [9 having a cylindrical intermediate portion I and end walls H and I2. The end wall ll comprises a centrally located boss l3 having a threaded opening it formed therein to which is connected a conduit leading from a welding cylinder (not shown) for the admission of air therefrom into a chamber A hereinafter described. This threaded opening 14, at its inner end portion, terminates in a counterbore 15 which in turn communicates with the chamber A. This chamber A is provided by the end wall ii and a diaphragm I5 formed of suitable material, such for example as stainless steel. Mounted in the counterbore between the boss i3 and the diaphragm I8 is a compression spring M. This end wall H and the diaphragm I 6 are connected to the intermediate portion Hi through the medium of bolts [3 threaded into openings l9.

Adjustably carried by the diaphragm i6 is \a threaded stud 2i! having a disc-shaped head 2 formed on one end portion thereof. This stud 2D is threaded through nuts 22, and the end 23 thereof has a screwdriver slot 24 formed therein whereby when the lock nut 25 is loosened the stud 20 may be adjusted relative to the mounting nuts 22.

The wall 12 carries a plug housing 26 into which an ordinary standard electric plu (not shown) is adapted to be mounted for connection with terminal posts 21 carried by the end wall as shown. These terminal posts 2! are connected to an electric switch 28 through the medium of conductor wires 29. This switch 28 is carried in any suitable manner by the wall l2, such for example by means of screws 30. This switch 28 constitutes no part of the present invention and is preferably of a structure substantially similar to that shown in U. S. Patent No. 2,289,108 granted July '7, 1942, to one Eaton. As shown in the drawing accompanying this application, this switch comprises a sleeve 3! through which a push rod 32 operates, the push rod 32 serving to operate the switch elements (not shown) illustrated in the patent hereinbefore referred to. This push rod 32 is disposed in the path of movement of the stud 20 when the stud 20 is moved longitudinally in a manner hereinafter described. This end wall i2 is connected to the intermediate housing portion l6 through the medium of bolts 33 threaded into the openings l9.

To complete the invention, I provide on the intermediate portion ill, mounting lugs 34 which facilitate mounting the pressure-operated switch on a, fixed object. In the intermediate portion H) of the housing [0 there is provided an opening 35 in which is mounted a conduit leading from a pressure check valve (not shown) which 3 in turn communicates with a pressure generating device of a standard equipment used in connection with pneumatically operated resistance welding machines.

My improved balanced pressure switch operates as follows:

The proper pressure to effectively operate a pneumatically operated resistance welding machine is admitted into the chamber B through the Opening by a pressure check valve (not shown) functioning to assure the admission of the proper degree of pressure into this chamber. When the pressure in the chamber B reaches the proper degree, the diaphragm will be caused to flex outwardly therefrom, This flexing of the diaphragm I6 will permit the switch 28 to open. The operator or the welding machine admits air into the welding cylinder (not shown) and when the pressure of this air has been built up in this welding cylinder to a point for proper welding operation, which is greater than the pressure of the air in chamber B, the air pressure in chamber A from this welding cylinderwill flex the diaphragm l6 in an opposite direction, closing the switch 28. So long as this proper air pressure is maintained in chamber .A, the switch 28 will remain closed and the welding machine properly operated by a stabilized air pressure through its pneumatic system. The spring I? functions to return the diaphragm IE to its normal unflexed position when the air pressure is equal in both chambers A and B. As previously pointed out, with a balanced pressure switch constructed in the manner hereinbefore described,

the pneumatic system of a pneumatically oper- 'ated resistance welding machine will be stabilized during its operative period to assure proper :and effective welding operation.

While I have illustrated and described the preferred form of construction for carrying my invention into efiect, this is capabl of variation :and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

1. A pressure balanced switch comprising a housing, a diaphragm in the housing dividing the same into opposed non-communicating chambers, a switch in one of said members and comprising a, push rod, means carried by the diaphragm and adapted to engage the push rod for moving the same in a direction to close said switch when the air pressure in one of saidchamhers is greater than the air pressure in the other of said chambers, means for admitting air under pressure to each of said chambers, and means carried by said housing and engaging said diaphragm for maintaining said diaphragm in an unflexed position when the air pressure in each of said chambers is equal.

2. A pressure balanced switch comprising a housing, a diaphragm in the housing dividing the same into opposed non-communicating chambers, a switch in one of said chambers and comprising a push rod, means carried by the diaphragm and adapted to engage the push rod for moving the same in a direction to close said switch when the air pressure in one of said chambers is greater than the air pressure in the other of said chambers, means for admitting air under pressure to each of said chambers, and

means carried by said housing and engaging said diaphragm for maintaining said diaphragm in an unfiexed position when the air pressure in each of said chambers is equal, said last-named means comprising a spring arranged between a wall of said housing and said diaphragm.

RAYMOND L. WILLIAMS. 

